The present invention relates generally to material handling attachments. In particular, the invention relates to an articulating truss boom that is securely attached to the end of a lifting machine. The articulating truss boom has an internal pivot joint that permits secure horizontal movement and usage of the articulating truss boom.
In the construction industry it is common to utilize attachments on material handling or other lifting machines in order to increase both the height and reach of the lifting machines. In addition, it is often necessary to refine the placement of such attachments as truss booms for carrying housing trusses. For example, after a material handling machine with an associated telescoping boom or other lifting machine has positioned a truss boom as close to its intended location as is practical in the vertical direction, it may be necessary to refine the orientation of the attachment in the horizontal direction. Previously, changing the horizontal orientation of the attachment involved moving the entire material handling or lifting machine and repositioning the entire apparatus for another attempt, which would not guarantee optimal orientation of the attachment. This procedure is time-consuming and potentially dangerous, moving the entire material handling machine may involve removing stabilizers and leveling equipment, backing up and repositioning the material handling machine with relatively heavy loads. Additionally, it may not always be possible to move the material handling machine closer to the desired location, as is the case when the machine would be parallel to a wall.
It would be advantageous to be able to place the truss boom into its final horizontal position by simply pivoting the truss boom while the truss boom was still securely attached to the telescoping boom or other implement of the material handling or lifting machine.
U. S. Pat. No. 4,159,059, issued to Christenson et al, discloses a truss boom for a material handling truck that is shown to horizontally move with the assistance of a fork assembly, tilt cylinder and the outer arm of an outer boom. The use of such a structure is dependent upon the availability of a fork lift or other fork assembly. Additionally, the fork assembly engages the truss boom and together they are pivoted by the tilt cylinder which is positioned between the fork assembly and the boom. The additional weight of the fork assembly on the load side of the pivot point significantly decreases the potential extension length and the load bearing capabilities of the truss boom, particularly at near limit extension lengths and loads for the particular machine. It would be advantageous, therefore, to have an articulating truss boom that increased the load bearing capabilities of the machine and that does not require the use of a particular type of machine.
Additionally, it is found that when a load in a truss boom, for example, is moved to the limit of its pivot arch in the horizontal direction, a contact is made between the pivot joint and the truss boom frame. This contact results in a relative motion of the entire machine due to the vibration of the contact, potentially a dangerous occurrence. It would therefore also be advantageous to provide some shock absorbing capability of the articulating truss boom to minimize the direct metal to metal contact which may cause undesirable vibrational swaying. Although the prior art discloses a truss boom that with assistance is capable of some horizontal movement with limited loads, it would be advantageous to have an articulating truss boom that solves the aforementioned problems not solved by the prior art.
The present invention provides an articulating truss boom that overcomes the aforementioned problems, and provides a truss boom that is capable of horizontally pivoting while carrying an appropriate load.
In accordance with one aspect of the invention, an articulating truss boom assembly for use with a lifting machine is provided and includes an articulating truss boom frame. The articulating truss boom assembly comprises a stationary support member which is attachable to a lifting machine, and an internal pivot assembly. The internal pivot assembly has a vertical pivot axis and is interposed between and provides a connection between the stationary support member and the articulating truss boom frame. The articulating truss boom frame is capable of pivoting with respect to the stationary support member about the vertical pivot axis in a horizontal plane. The horizontal plane is transverse to the vertical pivot axis.
In accordance with another aspect of the invention an articulating truss boom assembly for attachment to a lifting machine includes a stationary support member. The stationary support member includes a coupling assembly for coupling the stationary support member to the lifting machine. The coupling assembly comprises a support beam and a pair of securing members extending therefrom. Each securing member includes a hook portion and a securing lobe having an aperture therein. The hook portions and the securing lobes are capable of locking engagement with the lifting machine. The stationary support member further includes a first pair and a second pair of parallel stationary member support plates. Each pair of stationary member support plates has an aperture and includes a reinforcement plate transversely connected therebetween.
The articulating truss boom assembly further includes an articulating truss boom frame having a first pair and a second pair of truss boom support plates. Each pair of parallel truss boom support plates has an aperture and includes a truss boom frame reinforcement plate transversely connected therebetween. A pivot pin having a pivot sleeve is interposed between the stationary member and the articulating truss boom frame. An actuator member is connected to the pivot sleeve for pivoting the articulating truss boom frame in a horizontal pivot plane transverse to the pivot pin. The articulating truss boom assembly further includes a hydraulic assembly connected to the actuator to provide hydraulic fluid to the actuator and to facilitate pivoting of the articulating truss boom frame. The first and second pair of parallel stationary member support plates and the first and second pairs of parallel truss boom support plates are interlaced such that the parallel apertures of the stationary member support plates line up with the apertures of the parallel truss boom support plates. The support plates receive the pivot pin extending transversely therethrough.
In accordance with another aspect of the invention, the articulating truss boom assembly has a hydraulic assembly connected to the pivot sleeve. The hydraulic assembly includes an actuator and a hydraulic power cylinder securely mounted at a first end to the stationary support member. The hydraulic power cylinder has a hydraulic fluid connector extending therefrom. The hydraulic assembly further includes a moveable plunger arm inserted into a second end of the hydraulic power cylinder to permit translational movement of the moveable plunger arm. An actuator lever is connectable attached to the moevable plunger arm and has an aperature to receive the pivot pin therethrough. Tile actuator lever rotates with respect to the pivot pin and moves the articulating truss boom frame when the moveable plunger arm is in translational movement. A hydraulic control unit is connected to the stationary support member for supplying hydraulic fluid to the hydraulic power cylinder.
The hydraulic assembly further includes a metering valve connected to the fluid connector and operatively associated with the hydraulic power cylinder. The metering valve conducts hydraulic fluid from the hydrualic control unit to the hydraulic power cylinder. A restrictor is removeably inserted within the metering valve. The restrictor has a restricted channel therethrough to limit the hydraulic fluid channeled to the hydraulic power cylinder. Preferably, a plurality of rubber shock absorbing pads is attached to prevent direct contact of the stationary member and the articulating truss boom frame.
Accordingly, one object of the present invention is to provide an articulating truss boom that pivots in a horizonal direction.
Another object of the present invention is to provide an articulating truss boom that pivots in a controlled manner.
Yet another object of the present invention is to provide an articulating truss boom that minimizes metal to metal contact and vibrational swaying.
These, and other, aspects and objects of the present invention will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following description, while indicating preferred embodiments of the present invention, is given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the present invention without departing from the spirit thereof, and the invention includes all such modifications.